Fabrication and characterization of SiC/Al composites prepared by laser powder bed fusion (LPBF) combined with vacuum pressure infiltration
Guizhou Liu, Shixiang Zhou, Changshun Wang, Shuang Chen, Dong Sun, Annan Chen, Zhaoqing Li, Chunze Yan, Yusheng Shi
Abstract
A novel method has been developed to fabricate SiC/Al composites by the combination of laser powder bed fusion (LPBF) and vacuum-pressure infiltration. The effects of the SiC particle size distribution and pre-oxidation on the microstructure and properties of SiC/Al composites were investigated. A new phenomenon of severe lamellar cracking was observed in SiC/Al composites without pre-oxidation treatment, which can be explained in terms of the mechanism of interlayer binding. The results showed that the residual porosity of the sample without pre-oxidation treatment s was higher than 3%, with a maximum of (8.16 ± 0.57) %, which was much higher than that of the pre-oxidised samples(1% ∼2%). The bulk density of the powders was significantly improved by designing the material system with mono-, bi-, and tri-modal particle size distributions and the density of final SiC/Al samples gradually increases from 2.804 ± 0.009 to 2.871 ± 0.008 g/cm3, and the volume fraction of SiC increases from 36.7 vol% to 50.1 vol%. As a result, the coefficients of thermal expansion (CTE) of SiC/Al composites varies consistently with the volume fraction of SiC, decreasing from 13.72 to 10.84 × 10-6 °C−1. Our study shows that this method has the potential for great applications.